The present invention relates to a fluid treatment apparatus and method for treating industrial waste, or the like, and also for treating the waste with a predetermined liquid/gas contact in a series of treatments in the irradiator.
The importance of chemical contamination of fluids has become a significant factor in the handling and disposal of waste fluids. Chemicals that occur in water following conventional treatment are known to be dangerous to human health. New methods are needed to destroy the chemical structures of toxic materials that occur in water and other fluids. The present method uses a combination of ozone (O.sub.3), oxygen (O.sub.2) and gamma ray (.gamma.)irradiation to destroy the molecular structure of both chemical and biological toxic materials in fluids.
Previous irradiation patents have been primarily directed at destroying biological organisms within fluids. The present concept utilizes the combination of ozone (O.sub.3), oxygen (O.sub.2) and gamma rays (.gamma.) to break up the molecular structure of toxic chemicals and simultaneously destroy other biological organisms. However, to accomplish this objective, the ozonation aspects of the process must be shielded from the gamma rays. For certain toxic materials, it will be more effective to use chlorine (Cl.sub.2) rather than ozone (O.sub.3).
In experimental work performed during the past several years, it has been found that a sequential series of ozonation and irradiation was much more effective than just doubling the ozonation and/or irradiation. Thus, the apparatus must be designed to incorporate a sequential ozonation and irradiation which cannot occur in the same chambers because of the weak bond of the third oxygen atom which is immediately broken by the irradiation. The ozonation chamber must also be shielded by lead, concrete, or some other material to allow an interaction between the ozone (O.sub.3) and the toxic materials without strong gamma ray (.gamma.) irradiation.
In addition to the ozone (O.sub.3) or chlorine (Cl.sub.2) treatment in sequence with the irradiation, oxygen (O.sub.2) has been found to be an effective synergistic agent when used simultaneously with the gamma ray (.gamma.) irradiation. Thus, a hydrodetoxification system must also include the injection of oxygen (O.sub.2) or air into the irradiation chamber.
Decomposition of water and other fluids by gamma rays has been known to exist for many years. However, many of the observed results were difficult to explain until the hydrated electron was postulated in the early 1950's. Gamma rays (.gamma.) from both cobalt-60 and cesium-137 have energies so great that they both ionize and excite many liquid molecules along their path, as shown in the following equations: EQU H.sub.2 O+.gamma..fwdarw.H.sub.2 O.sup.+ +e.sup.- s EQU H.sub.2 O+.gamma..fwdarw.H.sub.2 O*
The electron removed from the water molecule has energy of a magnitude such that is also ionizes and excites other fluid molecules. As the electron loses energy, it becomes subexcitable, then thermal, and finally hydrolyzes in about 10.sup.-11 seconds as shown in the equation below: EQU e.sup.- s.fwdarw.e.sup.- se.fwdarw.e.sup.- t.fwdarw.e.sup.- ag
The positive water or other fluid ions also react with other water or fluid molecules. In water, a hydroxyle free radical is formed as shown in the following equation: EQU H.sub.2 O.sup.+ +H.sub.2 O.fwdarw.H.sub.3 O+OH.degree.
During this same period of time, the excited water molecules decompose into hydrogen free radicals and hydroxyle free radicals as shown in the equation below: EQU H.sub.2 O*.fwdarw.H.degree.+OH.degree.
These three reactive species e.sup.- .sub.eg H.degree. and OH.degree. are produced by the irradiation of water and other fluids and result in the decontamination of the fluid. Secondary effects within the fluids also result in the production of hydrogen peroxide, free hydrogen, peroxyle free radicals, and other ions. These secondary species increase the effectiveness of the irradiation to decompose toxic chemicals and biological materials.
Addition of oxygen or a halogen, such as chlorine, to a fluid during irradiation greatly increases the production of hydrated electrons and other reactive ionic species. Positive synergistic effects have been experimentally found to exist when specific materials were added to a fluid just prior to or during irradiation.
In addition to the primary effect of the gamma rays on chemicals contaminants and the secondary effects of the hydrated electrons and reactive ions, the gamma rays produce ultraviolet radiation throughout a large volume surrounding the cobalt-60 or cesium-137. When cobalt 60 or cesium-137 is placed in an aqueous environment, Cherenkov radiation is observed. This radiation is produced by electrons that have been knocked off the water molecules and possess a velocity greater than the velocity of light in the aqueous solution. The electrons produce a "bow-wave" of light or radiation that is primarily of the ultraviolet frequency. This "bow-wave" is similar to the "shock-wave" of a super sonic jet plane.
Because of the difference in the particle velocity and the phase velocity of light in the medium, there is no longer complete destructive interference and the electron radiates. This radiation is mostly in the ultraviolet part of the spectrum. However, when one sees Cherenkov radiation, they see only the blue tail of the radiated spectrum. The ultraviolet radiation is thus produced within the medium itself and the problem of minimal depth of penetration from an exterior UV source is eliminated. All of the detoxification and disinfection properties of ultraviolet radiation is obtained throughout the volume of the irradiator.
The present method and apparatus incorporates the combined effects of irradiation and ozonation to destroy both chemical and biological toxic materials. This method also uses the synergistic effects of ozone, oxygen, nitrogen, air, or any of the halogens to increase the effectiveness of the irradiation process.
Prior irradiators may be seen in my prior U.S. patents and especially to U.S. Pat. No. 3,865,734 for an Irradiator Apparatus which utilizes an irradiator having an irradiation source therein along with means to feed various gases into the irradiator. The gases suggested in this patent are chlorine, ozone and oxygen based upon my research. The present invention incorporates a number of significant improvements over my prior irradiator in U.S. Pat. No. 3,865,734. Improvements include the separation into a series of chambers to take advantage of the fact that irradiation is more effective in a series of irradiation treatments of the fluid. This is useful because radiation sources having a lower level of radiation, such as spent fuel from nuclear plants, can be effectively utilized in the irradiator. This allows the use of what would otherwise be waste nuclear sources. In addition, the ozonation and irradiation cannot occur in the same chamber because of the weak bond of the third oxygen atom which breaks down by the irradiation, thereby reducing the effectiveness of using ozone in the same chamber as the irradiation. Thus, one or more ozone chambers are provided which are shielded by lead, concrete, or some other material such as spent uranium, to reduce the effect of the radiation on the ozone during the liquid/gas contact with the ozone.
It has been found that irradiation in accordance with the irradiator of the present invention can dissociate chemicals such as carbon tetrachloride (CCl.sub.4) and chloroform (CHCl.sub.3) to free the chlorine atoms or to free the chlorine, ethane and methane from chlorinated phenolic waste and that these gases can then be reused in a production chain process such as in the production of poly-vinyl chloride (PVC) to recapture part of the waste while detoxifying the carbon tetrachloride, chloroform and other wastes.